Finished cover for underfloor junction box



Aug. 8, 1959 E. B. CLARK 2,900,101

' FINISHED COVER FOR UNDERFLOOR JUNCTION BOX Filed Sept. 50, 1957 [a k/J/v 5 (70%? 2/ W KM A2? A/fwwgg 2,900,10i FINISHED COVER FQRIJNDERFLOOR JUNCTION Box- Edward B. Clark, Milford,- .Qonrii, assignor t[GeneI-al Electric Company, a corporation of New York Application September 30,1957, serial No."687,329 2 Claims. (Cl 220-34 The present invention relates] to underfloor wirin distribution systems and particularly to afin"i'shed floor cover that may be installed as 'partofa standard'jun'ction box connectingthe intersecting runs of underfloor'duct. 7

Such junction boxes are sometimes called" duct boxes, are usually of heavy cast iron havingabotto'm wall, side walls and a top wall. side wanscomain duct-receiving openings, while the top "'wall includes a' large hole or access opening; usually flciiciilar in s'hape, so that" the wires may be installed theiductsw Underfloor duct systems; are widely used inlarge states" and office buildings of fire mbfcdnsmicaen where-the I V pp Eat duct' box has a handhole in its top wall'that is clos'edby' a re ducts are buried in the concrete flo'or.

movable floor cover and designed tolie flush with the concrete surface. Oftentim'e'sfit'i's desi'rabl'eto' cover the concrete with a finished flooring of wood," linoleum, or composition tile. Accordingly,-,it is necessary to provide a finished fioo r'cover over the box that will likewiseb e flush with the finished flooring The principal object of this yention is to provide an underfloor duct boxwith a finished 'floor cove that will be flu h wi h.. 1 -fi h.d flqqtin ia alsszhe means for protecting the edge of the finished flooring.

A further object of this invention is to provide a finished cover for a duct box of an underfloor wiring distribution system that incorporates the use of a novel trim ring for protecting the edge of the finished flooring where the flooring terminates adjacent the finished cover.

A still further object of this invention is to provide a finished cover of the class described with means for lifting the cover to gain access to the box.

The preferred embodiment of the present invention includes a finished cover that is inlaid with material similar to that of the finished flooring of the building. The top edge of the finished cover has a tapered side flange cooperating with a trim ring in which the cover is placed. The top inner edge of the trim ring is beveled or countersunk to receive the tapered flange of the finished cover and present a perfectly smooth surface extending over the several parts. The trim ring is placed on the concrete flooring and is centered over the floor cover of the duct box. The lower edge or base of the trim ring has an outer flange that is covered by the finished flooring as it is being laid. When the finished cover is removed, the trim ring is temporarily held in place by the finished flooring. However, when the finished cover is fastened down, the tapered side flange of thefinished cover will securely hold the trim ring in place.

My invention will be better understood from thefollowing description taken in connection with the accompanying drawing and its scope will'be pointed out in the appended claims. J

The single figure of the drawing is a perspective view of a typical floor construction shown in vertical crosssection through a duct box embodying my invention with the concrete fill and the finished flooring in place. 7

Referring in detail to the drawing, 10 designates a Patented 1 Aug. 18,1959- as C portion'o f the top wanst, a tandard duct be): havinga" handholeor access opening 11' that is 'definedby an up-' standing flange 121- A leveling'ring 13 is telescoped over the flangell and'it has a continuous'inner shelf or ledge 14 shownresting oni'theddp-surface of the flange. As

is the general"prac'tice,"the leveling ring -13 isvertically adjustable by means of elevating' screws (not shown)- that are threaded'iiitofltlietop wal1 10' ofthebox. Hence," if the"concrete fill 15were pouredin excess, it would'- be possible to raise" the} leveling ring '13 so than-its top surface would beifliish with'the topof the-concrete:

Since this vertical: adjustment is well knowri'in'this artj- 4 it is not deemed necessary -to"illustrate ifin tlie drawingas it does'notf form-part of thep're'sent invention.

A'n' annular rubber-gained is placed onthe' shelf 14 of the leveling ring-'aiidfa h'e'avy floor cover18 is sembled within theleveliii'gring and seated on the gasket to formf a sealed cover rat the -handhole; Several spaced? y of- 'tlie" shelf-14'and each contain 17 the gasltetmay be made-very simpleiwithouflany clearance'holes'aridtheneessity of aligning 'the'holes'with the openings 2 slightly depressedbelowf the upper surface of the level?- in ring-13 'and'concrete-fill 15;- fdr reasons which will; be explained 'hereinaftelt' Y A finished flooring- 25 usirch hardwood linoleum or composition-tileis often used over thQQOllr crete fill .152: .This presents theproblem; qf providing a removable coverzforfthejduct; box that willbeflush the top surface: of thejfinished flooring. ha bee solved-xingthe following ,-manrrer, with the inclus the finishedflogr' cover, 7 6iand rir ig flv flhreg finished cover 26 is of dish shape with a" b ott o'rri'wall 28- and a continuous side wall 29. A boss 30 is located in the center of the bottom wall and it has an oversized threaded opening 3 1 for loosely receiving a flat headed screw 32 that is to be threaded into a central opening 36 of the floor cover 18. The purpose of the threaded opening 31 in the boss 30 is to permit the easy removal of the finished cover. This is accomplished by first removing the screw 3-2 and then threading a larger size screw (not shown) into the opening 31 thereby making it possible to lift the finished cover out of the floor.

The recessed part of the finished cover is inlaid as designated at 33 with a slug of material that will match the finished flooring 25 placed over the concrete fill 15.. If the inlaid material 33 is of the same thickness as the finished flooring 25, which would be the usual case, it is necessary to depress the cover 18 below the top surface of the leveling ring 13 to allow for the thickness of the ma? terial of the bottom wall 28 of the finished cover, as is clearly shown in the drawing.

The trim ring 27 is seated on top of the leveling ring 13 and it is adapted to receive the finished cover 26 therein. It also overlies a portion of the concrete 15. The lower edge or base of the trim ring 27 has an outer flange 35 that is to be covered by the finished flooring 25. Accordingly, the steps taken to lay the finished flooring would be preceded by the positioning of the trim ring 27 over the leveling ring 13 and the fastening of 27 is beveled or countersunkas at 38 to receive the tapered flange so that when the finished cover is fastened down, it will securely hold the trim ring in place.

Having described above my invention of a finished cover and trim ring 'of novel construction, it should be readily apparent that the resulting floor structure would beprefectlysmooth, and the inner edge of the finished flooring would be well protected from abuse and permanent damage. ,Since the finished cover and trim ring produce a smooth top surface, it will be understood that the resulting floor would be safefor heavy pedestrian and truck traflic without fear of stumbling or damage to the appearance of the floor. Although I have chosen to illustrate my invention with the finished cover fastened indirectly to theleveling' ring 13 through the medium of the floor cover .18, it should be readily apparent to those skilled in this artthat the cover 18 could be completely eliminated and suitable screw means could be provided for the finished cover that would be threaded directly into the lugs 20 of the leveling ring 13.

Modification of this invention will occur to those skilled in this art and it is to be understood, therefore, that this invention is not limited to the particular embodiments disclosed but that it is intended to coverall modifications which are within the true spirit and scope of this invention.

What I claim as new and desire to secure by Letters Patent, of the United States is:

1. An underfloor ductbox comprising in combination an open top Wall that is defined by an upstanding circular flange, aleveling ring centered over the said flange and having a top surface adapted to be flush with the top of a. concrete slab, an inwardly directed ledge extending from the inner side of the leveling ring, a resilient gasket positioned on said ledge, and a metalcover plate seated on the gasket to close the top wall of the box, a trim ring seated on the leveling ring and having an outer flange at its lower end to-overlie the concrete and be coveredand held .down by a finished flooring that will lie flushwith the top'surface of the trim ring, and a finished cover supported by the trim ring and over the said cover plate, the finished cover including a tapered side flange adjacent its top surface for mating engagement with a beveled inner edge of the trim ring.

2. An underfloor duct box comprising in combination a hand hole in the top wall that is defined by an upstanding circular flange, a leveling ring telescopically arranged over the said flange and having an inwardly directed ledge extending from theinterior surface of the leveling ring, the underside of the said ledge being disposed over the top surface of the circular flange, a resilient gasket positioned on said ledge, and a metal cover plate seated on the gasket to close the open top wall of the box, the said ledge including several spaced lugs that extend inwardly of the said gasket and contain threaded apertures, there being mating holes in the cover for receiving flush-mounted fastening screws that are threaded into the said lugs, a trim ring fitted over the leveling ring with an outer flange at its lower end that is adapted to be covered and held down by a finished flooring that will lie flush with the top surface of the trim ring, and a finished cover assembled in the trim ring and overthe said cover plate, the finished cover including atop flange with a tapered underside for mating engagement with a beveled inner edge of the trim ring, and a fastening screw extending through an enlarged opening in the finished cover and threaded into the cover plate for holding the cover members together, the enlarged opening in the finished cover being threaded to facilitate the ready removal of the finished cover by means of a mating threaded member, thetop surface of the finished cover being inlaid with material that will correspond with the finished flooring.

References Cited in the file of this patent UNITED STATES PATENTS 1,533,759 Richardson et a1 Apr. 14, 1925 1,748,234 Loeb Feb. 25, 1930 1,921,057 Walker Aug. 8, 1933 1,949,883 Sharp Mar. 6, 1934 2,063,569 Walker Dec. 8, 1936 2,735,166 Hoseason Feb. 21, 1956 

